The present invention relates to a treatment fluid recovery apparatus, and in particular, it relates to a treatment fluid recovery apparatus for treating an elongate, continuously moving work product.
In standard operations today, huge amounts of treatment fluids which have a liquid phase and a heavier-than-air vapor phase within the operating range of temperatures are being emitted to the atmosphere in treatment operations involving elongate work products such as strip sheets, tubing and wire. These include, for example, III-trichlorethane, perchlor and trichlorethylene. Typically, the treatment operations involve spraying or flooding the work products in a treatment cell or other enclosure and above a container. The treatment cell itself and the container are ventilated in an attempt to maintain safe operating conditions in the area of this treatment operation. This ventilation process removes air and treatment fluid vapors directly from the spray area and treatment area. Typically, there is little or no attempt to recover these vapors in this air stream because the recovery process, such as carbon absorption and refrigeration, involves high maintenance and energy costs and could cause corrosion which results in unreliability of the system. The result of use of this type of system is that hundreds of thousands of pounds per year of treatment fluid vapors can be discharged and lost from a relatively small operation with great damage to the environment and at great cost to the user.
Patents which describe treatment fluid recovery apparatuses are Sabatka U.S. Pat. No. 3,896,829 issued Jul. 29, 1975, Sabatka U.S. Pat. No. 4,204,913 issued May 27, 1980, and Sabatka U.S. Pat. No. 4,289,586 issued Sep. 15, 1981. The Sabatka '829 patent describes an open top treatment tank used for chemically treating work pieces with a treatment fluid. A stage is provided to lower the work pieces to be treated into the tank where vapor condenses on the work pieces. A treatment tank lid closes the open tank top after the stage has brought the work into the tank. An agitated spray of fluid is directed against the work piece while the lid is in place. When the processing has been completed on the work piece, the stage and work piece are hoisted from the tank to allow liquid on the stage and work piece to drain back into the tank. A second lid closes the stage entrance.
The Sabatka '913 and '586 patents describe a solvent recovery apparatus and method having a treatment tank for chemically treating work pieces in a treatment fluid. The dirty or contaminated treatment fluid is reclaimed by confining it in a closed boiling vessel and boiling it off through a conduit back into vapor phase of the fresh fluid in an active operating treatment tank.